arXiv subjects

James Lindesay

Publications and source records attributed to James Lindesay.

At least 37 records · Page 2Linked to original sources

arXiv2008

Quantum Behaviors on an Excreting Black Hole

Often, geometries with horizons offer insights into the intricate relationships between general relativity and quantum physics. However, some subtle aspects of gravitating quantum systems might be difficult to ascertain using static backgrounds, since quantum mechanics incorporates dynamic measurability constraints (such as the uncertainty principle, etc.). For this reason, the behaviors of quantum systems on a dynamic black hole background are explored in this paper. The velocities and trajectories of representative outgoing, ingoing, and stationary classical particles are calculated and contrasted, and the dynamics of simple quantum fields (both massless and massive) on the space-time are examined. Invariant densities associated with the quantum fields are exhibited on the Penrose diagram that represents the excreting black hole. Furthermore, a generic approach for the consistent mutual gravitation of quanta in a manner that reproduces the given geometry is developed. The dynamics of the mutually gravitating quantum fields are expressed in terms of the affine parameter that describes local motions of a given quantum type on the space-time. Algebraic equations that relate the energy-momentum densities of the quantum fields to Einstein's tensor can then be developed. An example mutually gravitating system of macroscopically coherent quanta along with a core gravitating field is demonstrated. Since the approach is generic and algebraic, it can be used to represent a variety of systems with specified boundary conditions.

gr-qc↗

arXiv2008

An Exploration of the Physics of Spherically Symmetric Dynamic Horizons

Geometries with horizons offer insights into relationships between general relativity and quantum physics. For static spherically symmetric space-times, the event horizon is coincident with a coordinate anomaly that introduces complications in descriptions of near horizon physics. Naive introduction of dynamics using coordinates with anomalous behavior coincident with the horizon also introduces invariant singular physical content at that horizon. However, the introduction of a temporal coordinate that is non-orthogonal to spatial coordinates near the horizon, but asymptotically orthogonal, provides a dynamic description without singular physical content at the horizon itself. Penrose diagrams will be presented exhibiting temporal dependencies for accreting and evaporating black holes, and near horizon light-like trajectories will be examined. In addition, the quantum mechanics of simple quantum fields will be explored. Finally, a two-fluid cosmology will be suggested to describe dynamic coherent aspects of the universe as a whole.

gr-qc↗

arXiv2008

Radial Photon Trajectories Near an Evaporating Black Hole

The radial motion of photons emitted near the horizon of a black hole that evaporates at a steady rate is examined. The space-time of the black hole is generated using non-orthogonal coordinates. It is shown that some photons that are initially drawn towards the singularity can escape falling into the horizon. The behaviors of various outgoing and ingoing photons are clearly demonstrated through the use of a Penrose diagram.

gr-qc↗

arXiv2007

Construction of a Penrose Diagram for a Spatially Coherent Evaporating Black Hole

A Penrose diagram is constructed for an example black hole that evaporates at a steady rate as measured by a distant observer, until the mass vanishes, yielding a final state Minkowski space-time. Coordinate dependencies of significant features, such as the horizon and coordinate anomalies, are clearly demonstrated on the diagram. The large-scale causal structure of the space-time is briefly discussed.

gr-qc↗

arXiv2007

Insights into the Evolution of Horizons from Non-Orthogonal Temporal Coordinates

The introduction of coordinates representing the points of view of various observers results in the possibility of horizons when acceleration and gravitation are included. A horizon is a surface of possible light beams in a region of space of finite distance from the observer, which means that since nothing travels faster than light, events on the far side of a horizon cannot influence those on the causal side. A black hole has such a horizon, where some radially outgoing light beams can never reach a distant (or even nearby) observer. However, since one suspects that black holes can swallow energy, and even evaporate by Hawking radiation, such horizons must take on a time dependency. A naive introduction of temporal dependency results in infinities (singularities) in energy densities, suggesting in such descriptions that an in-falling observer would encounter a hard surface at the horizon. However, if coordinates representing space-time as analogous to a "flowing river" are used to describe the dynamics of a black hole, no such singularities are encountered. Such a parameterization of time dependent horizons will be offered in this presentation. A Penrose space-time diagram (which represents the entire space-time on a finite diagram with light beams always moving at a 45 degree angle to vertical) describing the growth and evaporation of an example black hole, along with the resulting coordinate anomaly, will be constructed.

gr-qc↗

arXiv2006

Coordinates with Non-Singular Curvature for a Time Dependent Black Hole Horizon

A naive introduction of a dependency of the mass of a black hole on the Schwarzschild time coordinate results in singular behavior of curvature invariants at the horizon, violating expectations from complementarity. If instead a temporal dependence is introduced in terms of a coordinate akin to the river time representation, the Ricci scalar is nowhere singular away from the origin. It is found that for a shrinking mass scale due to evaporation, the null radial geodesics that generate the horizon are slightly displaced from the coordinate singularity. In addition, a changing horizon scale significantly alters the form of the coordinate singularity in diagonal (orthogonal) metric coordinates representing the space-time. A Penrose diagram describing the growth and evaporation of an example black hole is constructed to examine the evolution of the coordinate singularity.

gr-qc↗

arXiv2006

A Conjecture for Using Optical Methods for Affecting Superfluid Hydrodynamics

The relation between the macroscopic quantum coherent nature of superfluids and the coherent properties of optical interference patterns will be utilized to examine the optical properties of superfluid hydrodynamics. A Bragg pattern imposed on the superfluid (either holographically or using a phase mask) is expected to induce periodic variations in the local index of refraction of the normal and super fluid components. The altered optical properties can then be probed by a second coherent light source. In this manner, the behavior of the probe beam can be switched using the specific characteristics of the imposed pattern. Acoustic modes should also manifest measurable affects on incident coherent radiations.

physics.optics↗

arXiv2006

Diagonal Forms of a Dual Scale Cosmology

A hybrid metric with off-diagonal temporal-radial behavior that was constructed to conveniently parameterized the early and late time behaviors of the universe is shown to have diagonal forms consistent with Robertson-Walker and deSitter geometries. The dynamics of the energy content of the cosmology as parameterized by the classical thermal fraction is briefly discussed as motivation for the comparison of the observables predicted by various micoscopic models of the early evolution of the universe.

gr-qc↗

arXiv2006

An Introduction of Multiple Scales in a Dynamical Cosmology

The discovery of scale acceleration evidenced from supernovae luminosities and spatial flatness of feature evolution in the cosmic microwave background presents a challenge to the understanding of the evolution of cosmological vacuum energy. Although some scenarios prefer a fixed cosmological constant with dynamics governed in a Friedman-Robertson-Walker (FRW) geometry, an early inflationary epoch remains a popular model for cosmology. It is therefore advantageous to develop a metric framework that allows a transition from an early inflationary period to a late stage dominated by dark energy. Such a metric is here developed, and some properties of this metric are explored.

gr-qc↗

arXiv2006

Thermal Evolution of a Dual Scale Cosmology

Previous work developed a space-time metric with two cosmological scales; one that conveniently describes the classical evolution of the dynamics, and the other describing a scale associated with macroscopic quantum aspects like vacuum energy. The present work expands upon the dynamics of these scales to demonstrate the usefulness of these coordinates for describing early and late time behaviors of our universe. A convenient parameter, the fraction of classical energy density, is introduced as a means to parameterize the various early time models for the microscopic input.

gr-qc↗

arXiv2006

Evidence for a Cosmological Phase Transition From the Dark Energy Scale

A finite vacuum energy density implies the existence of a UV scale for gravitational modes. This gives a phenomenological scale to the dynamical equations governing the cosmological expansion that must satisfy constraints consistent with quantum measurability and spatial flatness. Examination of these constraints for the observed dark energy density establishes a time interval from the transition to the present, suggesting major modifications from the thermal equations of state far from Planck density scales. The assumption that a phase transition initiates the radiation dominated epoch is shown under several scenarios to produce fluctuations to the CMB of the order observed. Quantum measurability constraints (eg. uncertainly relations) define cosmological scales bounded by luminal expansion rates. It is shown that the dark energy can consistently be interpreted as being due to the vacuum energy of collective gravitational modes which manifest as the zero-point motions of coherent Planck scale mass units prior to the UV scale onset of gravitational quantum de-coherence for the cosmology.

astro-ph↗

arXiv2005

Scientific Eschatology

The future evolution of the universe suggested by the cosmological model proposed earlier at this meeting by the authors is explored. The fundamental role played by the positive "cosmological constant" is emphasized. Dyson's 1979 paper entitled "Time Without End" is briefly reviewed. His most optimistic scenario requires that the universe be geometrically open and that biology is structural in the sense that the current complexity of human society can be reproduced by scaling up its (quantum mechanical) structure to arbitrary size. If the recently measured "cosmological constant" is indeed a fundamental constant of nature, then Dyson's scenario is, for various reasons, ruled out by the finite (De Sitter) horizon due to exponential expansion of the resulting space. However, the finite temperature of that horizon does open other interesting options. If, as is suggested by the cosmology under consideration, the current exponential expansion of the universe is due to a phase transition which fixes a physical boundary condition during the early radiation dominated era, the behavior of the universe after the relevant scale factor crosses the De Sitter radius opens up still other possibilities. The relevance of Martin Rees' apocalyptic eschatology recently presented in his book "Our Final Hour" is mentioned. It is concluded that even for the far future, whether or not cultural and scientific descendants of the current epoch will play a role in it, an understanding (sadly, currently lacking) of community and political evolution and control is essential for a preliminary treatment of what could be even vaguely called scientific eschatology.

physics.gen-ph↗

arXiv2003

Group Structure of an Extended Poincare Group

In previous papers we extended the Lorentz and Poincare groups to include a set of Dirac boosts that give a direct correspondence with a set of generators which for spin 1/2 systems are proportional to the Dirac matrices. The groups are particularly useful for developing general linear wave equations beyond spin 1/2 systems. In this paper we develop explicit group properties of the extended Poincare group to obtain group parameters that will be useful for physical calculations in systems which manifest the group properties. The inclusion of space-time translations will allow future explorations of the gauge properties inherent in the group structure.

math-ph↗

arXiv2003

An Extended Poincare Algebra for Linear Spinor Field Equations

When utilizing a cluster decomposible relativistic scattering formalism, it is most convenient that the covariant field equations take on a linear form with respect to the energy and momentum dispersion on the fields in the manner given by the Dirac form for spin ${1 \over 2}$ systems. The general spinor formulation for arbitrary spins given in a previous paper is extended to include momentum operators. Unitary quantum mechanical representations are developed for these operators, and physical interpretations are suggested.

math-ph↗

arXiv2003

Group Structure of an Extended Lorentz Group

In a previous paper we extended the Lorentz group to include a set of Dirac boosts that give a direct correspondence with a set of generators which for spin 1/2 systems are proportional to the Dirac matrices. The group is particularly useful for developing general linear wave equations beyond spin 1/2 systems. In this paper we develop explicit group properties of this extended Lorentz group to obtain group parameters that will be useful for physical calculations for systems which might manifest the group properties. This group is a subgroup of an extended Poincare group, whose structure will be developed in a subsequent paper.

math-ph↗

arXiv2003

Electroporation of Biological Cells Embedded in a Polycarbonate Filter

The electropermeabilization of biological cell membranes by the application of an external field occurs whenever an applied field exceeds a threshold value. For fields above this threshold value but less than another critical value, the pores formed in the membrane are transient or reversible. Several mechanisms have been proposed for the formation of these transient pores. Here we examine the local electric fields generated for the configuration of cells embedded in a polycarbonate filter, both in the region in and around the pore. We consider the shear forces created in the membrane due to the gradient of the field along the surface of the membrane, and the interaction of the charged molecules in the membrane with this field. A relationship between the electric field strength and the size of the pore formed is derived.

physics.bio-ph↗

arXiv2003

A Test of the Calculability of a Three Body Relativistic, Cluster Decomposable, Unitary, Covariant Scattering Theory

In this work a calculation of the cluster decomposable formalism for relativistic scattering as developed by Lindesay, Markevich, Noyes, and Pastrana (LMNP) is made for an ultra-light quantum model. After highlighting areas of the theory vital for calculation, a description is made of the process to go from the general theory to an eigen-integral equation for bound state problems, and calculability is demonstrated. An ultra-light quantum exchange model is then developed to examine calculability.

nucl-th↗

arXiv2003

Linear Spinor Field Equations for Arbitrary Spins

When utilizing a cluster decomposible relativistic scattering formalism, it is most convenient that the covariant field equations take on a linear form with respect to the energy and momentum dispersion on the fields in the manner given by the Dirac form for spin \half systems. A general spinor formulation is given for arbitrary spins by minimally extending the Lorentz algebra to include operators whose matrix representation give general Dirac matrices. The forms of these matrices are explicitly demonstrated for spin \half and spin 1 fields.

math-ph↗